Consulting dissertations and habilitations is a good option to get familiar with the state of the art in a certain field. The German National Library (DNB) offers the possibility of an online search of all theses which have been published in Germany. These theses are often available for download as an "electronic resource". If that is not the case, you can still access at least the table of contents and/or the literature references.

As an example, go to the DNB catalogue and type in the search keyword "end of life". You get 855 hits (last update: 25.04.2017). 20 of these hits are shown as thesis (filter - at the right-hand side). Twelve of them are available online (filter - online resources).